Otimização de processo eletrolítico usando elétrodo de alumínio para remoção de tetraciclina em meio aquoso

Abstract

Due to the continuous use of drugs from different classes, medications have become persistent compounds in the environment. Antibiotics, when inserted into ecosystems, contribute to the emergence of resistant bacterial strains. Therefore, antimicrobials belong to the group of substances considered emerging contaminants, as they are compounds capable of accumulating in compartments and do not have legislation that regulates risk concentrations in environmental matrices, such as effluents, water, surface water, and groundwater. Tetracycline (TCT) is an antibiotic whose structure presents high chemical stability, a physical-chemical characteristic common to drugs. Thus, in this research, we sought to study the optimal conditions for removing TCT in an aqueous medium by applying the electrolytic process using a laboratory-scale reactor operated in batches with aluminum electrodes. The variables studied involved the voltage, pH, and concentration of the supporting electrolyte (Na2S2O3), defined by the 2³ complete factorial design, and optimized using the central composite rotational method (DCCR). After optimization, TCT removal kinetics were evaluated for 240 min. The best experimental condition obtained was pH=4.6; voltage=1.3 V and [Na2S2O3] =0.2 g L-1, with expected removal of 60%. The removal kinetics followed the behavior of the second-order model, with R² of 0.99. In general, the electrolytic process proved to be favorable for the removal of TCT in aqueous media.